Polymers of ethylene and other olefins are important items of commerce, and these polymers are used in a myriad of ways, from low molecular weight polyolefins being used as a lubricant and in waxes, to higher molecular weight grades being used for fiber, films, molding resins, elastomers, etc. In most cases, olefins are polymerized using a catalyst, often a transition metal compound or complex. These catalysts vary in cost per unit weight of polymer produced, the structure of the polymer produced, the possible need to remove the catalyst from the polyolefin, the toxicity of the catalyst, etc. Due to the commercial importance of polymerizing olefins, new polymerization catalysts are constantly being sought.
Arylaminotropones are useful as chemical intermediates, for instance in the synthesis of pharmaceuticals and pesticides.
Nickel complexes of various neutral ligands and monoanionic ligands are known as catalysts for the polymerization of ethylene and other olefins, see for instance (for monoanionic ligands) U.S. Pat. No. 6,060,569, WO9830609 (corresponding to U.S. patent application Ser. No. 09/006536, filed Jan. 13, 1998) and WO9842664, which are incorporated by reference herein for all purposes as if fully set forth. None of these references describe the use of aminotropones as ligands for nickel containing olefin polymerization catalysts.
Anilinotropones, especially 2-anilinotropones, have been made by a variety of methods, see for instance K. Kikuchi, Bull. Chem. Soc. Jpn., vol. 51, p. 2338 (1978); T. Nozoe, Bull. Chem. Soc. Jpn., vol. 51, p. 2185 (1978); and W. R. Brasen, J. Am. Chem. Soc., vol. 83, p. 3125 (1961). The methods described in these references are different from the methods described herein. In addition, yields of the desired 2-anilinotropones are generally lower than reported herein, and/or sterically hindered less basic arylamines are not used in the synthesis thereof.